Git is a free and open source distributed version control system designed to handle everything from small to very large projects with speed and efficiency. - git-scm.com
In more practical terms, git is a tool for working on software projects and lets you manage your work and the work of your partners more effectively over the life of your project.
- Repository: a project in git; like an application, a software library, or a course syllabus. Also referred to as a repo.
- Branch: A timeline of work in your repo. A repo consists of a master branch and any number of branches off of that. Branches can be used to develop code in isolation of other branches. Since branches are recursive, you can branch off a branch (and then branch off of that branch, etc. etc.).
- Commit: an atomic amount of work that lives on a branch. Typically these are a collection of diffs, which are a list of the files or lines that have been added or subtracted from a file; for example, this correction of a list of items:
--- a/FAVORITE_THINGS.md
+++ b/FAVORITE_THINGS.md
A list of my favorite musical notes:
* DO
* RE
- * FA
+ * MI
- Merge: Combining two branches together. Let's say branch A has a file called
Foo.javaand branch B has a file calledBar.java. Merging branch B into A would result in branch A having bothFoo.javaandBar.java - Conflict: When two branches cannot be merged without a correction. Typically, this requires you to identify which lines in a diff should go in the target branch. For example, if two people write different code for a function in separate branches, the person doing the merge would need to decide which lines to keep and which to get rid of:
--- a/example.js
+++ b/example.js
function print() {
<<<<<<< HEAD:branch-a
console.log('hello world!')
=======
console.log('goodbye world!')
>>>>>>> 8f8588aa64:branch-b
}
- Pull Request: A formal way of declaring that you want to merge two branches, usually requiring the approval of your partners and/or some review. Pull requests are not a built-in feature of git, but different implementations of git allow you to set up rules that are appropriate for your repo.
Git is "distributed" because your repos exist on your computer and in the cloud, requiring you to sync repos between your local and your remote. One such provider of git is Github, which will be used in this course. Other popular git include Bitbucket and GitLab, and some organizations host their own git environments for securty or privacy's sake.